[Elecraft] OT: Long loop antennas

[Ron D'Eau Claire]

Take a look in the literature for information on "Rhombic" and "Vee-Beam"
antennas as well, especially Rhombics which are diamond-shaped horizontal
loops open at the far corner. I just did a quick check and found an
interesting site with some history and mentions free design software at
http://tinyurl.com/37fkm

These are very effective and well-understood antennas that have been around
for 70 years or more. They were the choice of many commercial installations
for reliable long-haul communications across a very wide frequency range
encompassing much of the HF spectrum. The above link has some pictures of
their use at an RCA station. 

Like all horizontal antennas, low radiation angles require good height -
something approaching 1/2 wavelength. However, they can be excellent
short-skip antennas on frequencies where they aren't 1/2 wavelength up. 

Few Hams have much experience with them because most of us simply don't have
the room. But if you do, they are worth the effort! 

Keep in mind that they are directional! That's where the gain comes from.
And it's harder to rotate a giant loop than a beam. But they don't have to
be all that directional, and if you can orient one in the general direction
of primary interest, the results can be spectacular! Also, depending upon
how you set it up, you can make the antenna bi-directional or  reverse the
direction electrically. 

While it's possible to build such an antenna to operate with a low SWR on
the feedline (usually 600 ohm open wire line), the more typical installation
will use open wire line with a tuner. Of course, with today's remotable
ATU's, you might consider mounting an ATU at the feed point to provide a low
SWR match to coax for the run to the shack if open wire line is a problem. 

Ron AC7AC

-----Original Message-----

Summer is here and time for antenna work.  I have a fair amount of room and
am contemplating replacing my 3 element beam and vertical with a long loop
antenna (to simplify).  I can accommodate a loop up to 190' per side
(square) at the same height as the beam (45 feet).  I am looking for an all
band (160 to 10M) solution. I have been reading the messages on the
YahooGroups loop antenna reflector, but they seem devoted to "magnetic"
(short) loops.

Any sage comments from the group?  Do I need a tuner?  Should the tuner be
at the antenna or the rig?  Any books or articles I should be reading?

Thanks

Dave
VE6DRW
K2 S/N: 2171